Mapping the evolving strain field during continental breakup from
... micro-cracks generating a fast-polarization direction perpendicular to the minimum horizontal stress (SHmin)26. Such stress-induced anisotropy is most pronounced nearest the surface and the effect decreases with depth as the confining pressure increases, causing micro-cracks to close27. A model of s ...
... micro-cracks generating a fast-polarization direction perpendicular to the minimum horizontal stress (SHmin)26. Such stress-induced anisotropy is most pronounced nearest the surface and the effect decreases with depth as the confining pressure increases, causing micro-cracks to close27. A model of s ...
Abyssal peridotites, very slow spreading ridges and
... suggests a highly segmented crustal structure, with anomalously thin crust near fracture zones that may consist of only a thin veneer of pillow basalt erupted over mantle peridotite. The dredged peridotites underwent high degrees of melting, spanning the range believed to produce abyssal basalt. The ...
... suggests a highly segmented crustal structure, with anomalously thin crust near fracture zones that may consist of only a thin veneer of pillow basalt erupted over mantle peridotite. The dredged peridotites underwent high degrees of melting, spanning the range believed to produce abyssal basalt. The ...
2. Geology and tectonics of the Aegean - diss.fu
... which results in a slip velocity of 24 mm/yr in the North Anatolian Fault (McClusky et al., 2000). This westward motion of Anatolia does not result in a compressional field in the Aegean area, which on the contrary, is dominated by an extensional stress field. Moreover, the Aegean moves as a more or ...
... which results in a slip velocity of 24 mm/yr in the North Anatolian Fault (McClusky et al., 2000). This westward motion of Anatolia does not result in a compressional field in the Aegean area, which on the contrary, is dominated by an extensional stress field. Moreover, the Aegean moves as a more or ...
Plate Tectonics Jeopardy
... What volcanic mountain range is forming in South America as a result of the South American plate colliding with an oceanic plate? ...
... What volcanic mountain range is forming in South America as a result of the South American plate colliding with an oceanic plate? ...
Adakitic magmas: modern analogues of Archaean granitoids
... Both geochemical and experimental petrological research indicate that Archaean continental crust was generated by partial melting of an Archaean tholeiite transformed into a garnet-bearing amphibolite or eclogite. The geodynamic context of tholeiite melting is the subject of controversy. It is assum ...
... Both geochemical and experimental petrological research indicate that Archaean continental crust was generated by partial melting of an Archaean tholeiite transformed into a garnet-bearing amphibolite or eclogite. The geodynamic context of tholeiite melting is the subject of controversy. It is assum ...
Hotspots and Melting Anomalies - Earth and Environmental Sciences
... An intriguing, yet enigmatic form of age-progressive volcanism is represented by the PukaPuka and Sojourn Ridges, which extend NW away from the East Pacific Rise. With respect to its geographic trend and duration, the Puka-Puka Ridge resembles some of the other volcano chains the region, such as the ...
... An intriguing, yet enigmatic form of age-progressive volcanism is represented by the PukaPuka and Sojourn Ridges, which extend NW away from the East Pacific Rise. With respect to its geographic trend and duration, the Puka-Puka Ridge resembles some of the other volcano chains the region, such as the ...
Ophiolites and Their Origins
... magmatic, tectonic, and hydrothermal processes associdefi nition of suprasubduction zone ophiolites in the early ated with seafloor spreading prior to 170 Ma because no 1980s. Observations of in situ oceanic crust in spreading oceanic lithosphere older than this age is preserved in the environments ...
... magmatic, tectonic, and hydrothermal processes associdefi nition of suprasubduction zone ophiolites in the early ated with seafloor spreading prior to 170 Ma because no 1980s. Observations of in situ oceanic crust in spreading oceanic lithosphere older than this age is preserved in the environments ...
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... These were all, however, isolated locations and it was not until the mid-1980s that Hawkins and coworkers completed the first systematic sampling programs of the Lau Basin and Mariana Trough [summarized in Hawkins and Melchior, 1985] and confirmed the presence in back-arc basins of both MORB and bas ...
... These were all, however, isolated locations and it was not until the mid-1980s that Hawkins and coworkers completed the first systematic sampling programs of the Lau Basin and Mariana Trough [summarized in Hawkins and Melchior, 1985] and confirmed the presence in back-arc basins of both MORB and bas ...
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... he also measured Q for S waves finding values of 700 at 12 s and 400 at 24 s. Press (1956) also determined Q for S waves finding it to be 500 or less. Evernden (1955) studied the arrival directions of SV-, Rayleigh- and Love-wave phases using a tripartite array in California and found that all of th ...
... he also measured Q for S waves finding values of 700 at 12 s and 400 at 24 s. Press (1956) also determined Q for S waves finding it to be 500 or less. Evernden (1955) studied the arrival directions of SV-, Rayleigh- and Love-wave phases using a tripartite array in California and found that all of th ...
3 Factors controlling the crustal density structure - diss.fu
... scale for the decrease of H with depth and k = 2.5 W/m°C is thermal conductivity [Turcotte and Schubert, 2002, p.147]. With this parameterisation, the 1D thermal structure of the continental lithosphere depends exclusively on the surface heat flow density Qs. Common variance in Qs (±5 mW/m2), k (±0. ...
... scale for the decrease of H with depth and k = 2.5 W/m°C is thermal conductivity [Turcotte and Schubert, 2002, p.147]. With this parameterisation, the 1D thermal structure of the continental lithosphere depends exclusively on the surface heat flow density Qs. Common variance in Qs (±5 mW/m2), k (±0. ...
From oceanic plateaus to allochthonous terranes: Numerical
... the Caribbean (Kerr et al., 1997; Kerr and Tarney, 2005) are believed to have formed through extensive accretion along its active margin. Schubert and Sandwell (1989) have estimated an upper bound to the continental crust addition rate by the accretion of all oceanic plateaus to be 3.7 km3/year, whi ...
... the Caribbean (Kerr et al., 1997; Kerr and Tarney, 2005) are believed to have formed through extensive accretion along its active margin. Schubert and Sandwell (1989) have estimated an upper bound to the continental crust addition rate by the accretion of all oceanic plateaus to be 3.7 km3/year, whi ...
Characteristic thermal regimes of plate tectonics
... Early plate-like behavior may have allowed crust to float to form thick stacks above zones of boundary-layer downwelling (Davies, 1992), or, for a slightly cooler Earth, thick stacks above zones of “sublithospheric” subduction (van Hunen et al., this volume), but these behaviors are unlikely to have ...
... Early plate-like behavior may have allowed crust to float to form thick stacks above zones of boundary-layer downwelling (Davies, 1992), or, for a slightly cooler Earth, thick stacks above zones of “sublithospheric” subduction (van Hunen et al., this volume), but these behaviors are unlikely to have ...
Deep Earth Structure – Q of the Earth from Crust to Core.
... In order to reconcile teleseismic S–P differential traveltimes measured by handpicking, on the one hand, and by comparison of observed and synthetic seismograms, on the other, Oki et al.l (2000) found that a frequency dependence with 0.04 needs to be introduced in the reference PREM Q model (Dzi ...
... In order to reconcile teleseismic S–P differential traveltimes measured by handpicking, on the one hand, and by comparison of observed and synthetic seismograms, on the other, Oki et al.l (2000) found that a frequency dependence with 0.04 needs to be introduced in the reference PREM Q model (Dzi ...
Geological and geophysical evidence for large
... of active lithospheric extension suggest that there is no reason to think that the observed fault throws near the surface are not the superficial expression of large crustal faults. On the other hand, as it is suggested by Scholz (1990), the existence of an upper cut-off in seismicity seems limited ...
... of active lithospheric extension suggest that there is no reason to think that the observed fault throws near the surface are not the superficial expression of large crustal faults. On the other hand, as it is suggested by Scholz (1990), the existence of an upper cut-off in seismicity seems limited ...
•Earthquakes and Tectonics •Rupture mechanics and modelling
... Plates should not regarded static features. Heat from Earth’s core generates huge convection cells in the viscous mantle of the Earth. Plate motion is driven by friction at their base. The high weight of the plates also promotes plate motion during plate subduction. ...
... Plates should not regarded static features. Heat from Earth’s core generates huge convection cells in the viscous mantle of the Earth. Plate motion is driven by friction at their base. The high weight of the plates also promotes plate motion during plate subduction. ...
(PDF 8mb)
... both regional and broad scale tectonic implications. In particular, results from this project will help define what constitutes the boundaries of blocks of Alaska crust, and whether the wide plate boundary zone between the Pacific and North American plates is best characterized by diffuse deformatio ...
... both regional and broad scale tectonic implications. In particular, results from this project will help define what constitutes the boundaries of blocks of Alaska crust, and whether the wide plate boundary zone between the Pacific and North American plates is best characterized by diffuse deformatio ...
physical, chemical, and chronological characteristics of
... begins immediately beneath the Moho, with a high-velocity ‘‘lid’’ similar to that seen in ocean basins notably absent. Low-velocity zones beneath stable continental regions tend to be either extremely weak or entirely absent. As a result the base of the continental lithosphere is not well defined by ...
... begins immediately beneath the Moho, with a high-velocity ‘‘lid’’ similar to that seen in ocean basins notably absent. Low-velocity zones beneath stable continental regions tend to be either extremely weak or entirely absent. As a result the base of the continental lithosphere is not well defined by ...
View - GFZpublic
... 1. Introduction [2] Collisions between continents and volcanic island arcs are common elements in the ancient to recent tectonic history of the Earth. Many of these collisions are oblique and diachronous, starting where the two plates first collide then closing gradually like a zipper. This implies ...
... 1. Introduction [2] Collisions between continents and volcanic island arcs are common elements in the ancient to recent tectonic history of the Earth. Many of these collisions are oblique and diachronous, starting where the two plates first collide then closing gradually like a zipper. This implies ...
Global tectonics - Scheme of work and lesson plan booklet
... ensure that every young person has the opportunity to reach their full potential ...
... ensure that every young person has the opportunity to reach their full potential ...
Origin of marginal basins of the NW Pacific and their plate tectonic
... Geometry of basins can indicate their tectonic origin whether they are small or large. The basins of Bohai Gulf, South China Sea, East China Sea, Japan Sea, Andaman Sea, Okhotsk Sea and Bering Sea have typical geometry of dextral pull-apart. The Java, Makassar, Celebes and Sulu Seas basins together ...
... Geometry of basins can indicate their tectonic origin whether they are small or large. The basins of Bohai Gulf, South China Sea, East China Sea, Japan Sea, Andaman Sea, Okhotsk Sea and Bering Sea have typical geometry of dextral pull-apart. The Java, Makassar, Celebes and Sulu Seas basins together ...
GEO144_mid_term_I_so..
... (1) 2 pts.________ rocks form by crystallization and consolidation of molten magma. A) Igneous B) Primary C) Sedimentary D) Indigenous (1) 2 pts.________ rocks always originate at the surface of the solid Earth. A) Secondary B) Sedimentary C) Igneous D) Metamorphic (1) 2 pts.________ is the process ...
... (1) 2 pts.________ rocks form by crystallization and consolidation of molten magma. A) Igneous B) Primary C) Sedimentary D) Indigenous (1) 2 pts.________ rocks always originate at the surface of the solid Earth. A) Secondary B) Sedimentary C) Igneous D) Metamorphic (1) 2 pts.________ is the process ...
earthquake Andaman − Lessons from the 2004 Sumatra
... earthquake. Thus, in this case, the precursor cannot be used for a definitive earthquake prediction. Some large earthquakes were preceded by a distinct foreshock activity, but many earthquakes do not have distinct foreshocks. Also, a group of small earthquakes can occur without any major earthquake f ...
... earthquake. Thus, in this case, the precursor cannot be used for a definitive earthquake prediction. Some large earthquakes were preceded by a distinct foreshock activity, but many earthquakes do not have distinct foreshocks. Also, a group of small earthquakes can occur without any major earthquake f ...
Mechanism and timing of Pb transport from subducted oceanic crust
... New high-precision (double-spike) Pb isotope analyses of lavas from Tafahi and Niuatoputapu, the northernmost islands of the Tonga–Kermadec Island Arc, are used to examine the source of Pb in these samples, and the relative timing of Pb addition from the subducting oceanic crust and subducting sedim ...
... New high-precision (double-spike) Pb isotope analyses of lavas from Tafahi and Niuatoputapu, the northernmost islands of the Tonga–Kermadec Island Arc, are used to examine the source of Pb in these samples, and the relative timing of Pb addition from the subducting oceanic crust and subducting sedim ...
PDF 51 - The Open University
... book The Age of the Earth. Importantly, his second famous book Principles of Physical Geology did not follow the traditional viewpoints and concluded with a chapter describing continental drift. 1940-1960 The complexity of ocean floor topography was realised through improvements to sonar equipment d ...
... book The Age of the Earth. Importantly, his second famous book Principles of Physical Geology did not follow the traditional viewpoints and concluded with a chapter describing continental drift. 1940-1960 The complexity of ocean floor topography was realised through improvements to sonar equipment d ...
Post-glacial rebound
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Post-glacial rebound (sometimes called continental rebound) is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostatic depression. Post-glacial rebound and isostatic depression are different parts of a process known as either glacial isostasy, glacial isostatic adjustment, or glacioisostasy. Glacioisostasy is the solid Earth deformation associated with changes in ice mass distribution. The most obvious and direct affects of post-glacial rebound are readily apparent in northern Europe (especially Scotland, Estonia, Latvia, Fennoscandia, and northern Denmark), Siberia, Canada, the Great Lakes of Canada and the United States, the coastal region of the US state of Maine, parts of Patagonia, and Antarctica. However, through processes known as ocean siphoning and continental levering, the effects of post-glacial rebound on sea-level are felt globally far from the locations of current and former ice sheets.